Pyrylium sensitizers for photoconductive compositions

Abstract

Sensitizers for photoconductive compositions and elements are disclosed. The sensitizers are 2,4,6 tri substituted pyrylium dye salts wherein at least one of said substituents is a 5 or 6 membered heterocyclic ring having at least one atom selected from the group consisting of N, O and S.

We claim: 
     
       1. An aggregate photoconductive composition comprising a continuous electrically-insulating polymer phase and at least one discontinuous phase dispersed in said continuous phase, said discontinuous phase comprising a particulate co-crystalline complex of (i) at least one polymer having an alkylidene diarylene group in the recurring unit thereof, (ii) and at least one 2,4,6-trisubstituted pyrylium dye salt having the formula: ##STR7## in which R 1  and R 2  represent a phenyl radical, thienyl, furyl, pyridyl, pyrrolyl, pyrimidinyl, thiadiazolyl or thiazolyl, R 3  represents an alkylamino-substituted phenyl radical having from 1 to 6 carbon atoms in the alkyl moiety, dialkylaminopyridyl, dialkylaminofuryl, dialkylaminothienyl, dialkylaminopyrimidinyl, dialkylaminothiaiazolyl or dialkylaminothiazolyl; X represents oxygen or sulfur; Z represents an anion and wherein at least one of R 1 , R 2  and R 3  is one of the above enumerated heterocyclic moieties. 
     
     
       2. An aggregate photoconductive composition according to claim 1 wherein said continuous phase contains an organic photoconductor. 
     
     
       3. An aggregate photoconductive composition according to claim 1 wherein X is sulfur. 
     
     
       4. An aggregate photoconductive composition according to claim 1 in which X is sulfur and said continuous phase comprises an organic photoconductor. 
     
     
       5. An aggregate photoconductive composition according to claim 1 in which R 1  and R 2  represent phenyl, 2-thienyl, 3-thienyl, 2-furyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 3-pyrrolyl or 2-pyrimidinyl; 1,3,4-thiadiazol-2-yl or 2-thiazolyl; R 3  represents 4-dimethylaminophenyl, 4-dimethylamino-3-pyridyl or 5-dimethylamino-2-thienyl; X is oxygen or sulfur and Z is hexafluorophosphate or perchlorate. 
     
     
       6. An aggregate photoconductive composition according to claim 1 in which R 1  and R 2  represent phenyl, 2-thienyl, 3-thienyl, 2-furyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 3-pyrrolyl, 2-pyrimidinyl, 1,3,4-thiadiazol-2-yl or 2-thiazolyl; R 3  represents 4-dimethylaminophenyl or 4-dimethylamino-3-pyridyl or 5-dimethylamino-2-thienyl; X represents sulfur and Z represents hexafluorophosphate, fluoroborate or perchlorate. 
     
     
       7. An aggregate photoconductive composition according to claim 1 in which R 1  and R 2  represent phenyl, 2-thienyl, 3-thienyl, 2-furyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 3-pyrrolyl or 2-pyrimidinyl, 1,3,4-thiadiazol-2-yl or 2-thiazolyl; R 3  represents 4-dimethylaminophenyl 4-dimethylamino-3-pyridyl or 5-dimethylamino-2-thienyl; X represents oxygen or sulfur and Z represents hexafluorophosphate, fluoroborate or perchlorate and said continuous phase contains an organic photoconductor. 
     
     
       8. An aggregate photoconductive composition according to claim 1 in which R 1  and R 2  represent phenyl, 2-thienyl, 3-thienyl, 2-furyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 3-pyrrolyl, 2-pyrimidinyl, 1,3,4-thiadiazol-2-yl or 2-thiazolyl; R 3  represents 4-dimethylamino-phenyl, 4-dimethylamino-3-pyridyl or 5-dimethylamino-2-thienyl; X represents sulfur and Z represents hexafluorophosphate, fluoroborate or perchlorate, and said continuous phase contains an organic photoconductor. 
     
     
       9. An aggregate photoconductive composition according to claim 1 in which the continuous and discontinuous phases comprise a polymer having an alkylidene dianylene group in the recurring unit. 
     
     
       10. An aggregate photoconductive composition according to claim 1 in which the polymer in the discontinuous phase is a electrically insulating carbonate polymer having an alkylidene diarylene moiety as a recurring unit. 
     
     
       11. An aggregate photoconductive composition according to claim 1 in which the 2,4,6-trisubstituted pyrylium dye salt is selected from the group consisting of 4-(4-dimethylaminophenyl)-2-phenyl-6-(2-thienyl)thiopyrylium fluoroborate; 4-(4-dimethylaminophenyl)-2-phenyl-6-(2-thienyl)thiopyrylium perchlorate; 2-(2-thienyl)-4-(4-dimethylaminophenyl)-6-(3-thienyl)thiopyrylium fluoroborate; 4-(4-dimethylaminophenyl)-2-(2-furyl)-6-phenylthiopyrylium perchlorate; 4-(4-dimethylamino-3-pyridyl)-2,6-diphenylthiopyrylium perchlorate; 2-(3-pyridyl)-4-(dimethylaminophenyl)-6-(2-thienyl)thiopyrylium perchlorate; 2,6-di(2-furyl)-4-(4-dimethylaminophenyl)thiopyrylium perchlorate; 4-(4-dimethylaminophenyl)-2,6-di(2-thienyl)thiopyrylium perchlorate; 2,6-di(2-thienyl)-4-(4-dimethylaminophenyl)pyrylium fluoroborate; 4-(4-dimethylaminophenyl)-2-phenyl-6-(2-pyrimidinyl)thiopyrylium perchlorate; 4-(4-dimethylaminophenyl)-2-phenyl-6-(1,3,4-thiadiazol-2-yl)thiopyrylium perchlorate; 4-(4-dimethylaminophenyl)-2-phenyl-6-(2-thiazolyl)thiopyrylium perchlorate; 4-(5-dimethylamino-2-thienyl)-2,6-diphenylthiopyrylium perchlorate or 4-(4-dimethylaminophenyl)-2-phenyl-6-(3-pyrrolyl)thiopyrylium perchlorate. 
     
     
       12. A photoconductive insulating composition comprising an electrically-insulating polymeric binder, photoconductor and a sensitizing amount of a sensitizer for said compound wherein said sensitizer is selected from a 2,4,6-trisubstituted pyrylium dye salt having at least one heterocyclic substituent being a 5 to 6 member ring wherein said ring has at least one atom selected from the group consisting of H, O or S, provided that said heterocyclic substituent is other than pyrylium or thiopyrylium. 
     
     
       13. A photoconductive insulating composition according to claim 12, wherein the photoconductor is an organic compound. 
     
     
       14. A photoconductive insulating composition comprising an electrically-insulating polymeric binder, a photoconductor compound and a sensitizing amount of a sensitizer for said photoconductive compound, said sensitizer being a 2,4,6-trisubstituted pyrylium dye salt having the formula: ##STR8## in which R 1  and R 2  represent a phenyl radical, thienyl, furyl, pyridyl, 3-pyrrolyl, pyrimidinyl, thiadiazolyl or thiazolyl; R 3  represents an alkylamino-substituted phenyl radical, dialkylaminopyridyl, dialkylaminofuryl, dialkylaminothienyl, dialkylaminopyrimidinyl, dialkylaminothiadiazolyl or dialkylaminothiazolyl; X represents oxygen or sulfur and Z represents an anion and wherein at least one of R 1 , R 2  and R 3  is one of the above enumerated heterocyclic moieties. 
     
     
       15. An organic photoconductive insulating composition comprising an electrically-insulating polymeric binder, an organic photoconductor and a sensitizing amount of sensitizer for said organic photoconductor, said sensitizer being a 2,4,6-trisubstituted pyrylium dye salt having the formula: ##STR9## in which R 1  and R 2  represent an phenyl radical, thienyl, furyl, pyridyl, 3-pyrrolyl, pyrimidinyl, thiadiazolyl or thiazolyl; R 3  represents an alkylamino-substituted phenyl radical, dialkylaminopyridyl, dialkylaminofuryl, dialkylaminothienyl, dialkylaminopyrimidinyl, dialkylaminothiadiazolyl or dialkylaminothiazolyl; X is oxygen or sulfur and Z is an anion and wherein at least one of R 1 , R 2  and R 3  is one of the above enumerated heterocyclic moieties. 
     
     
       16. An organic photoconductive insulating composition according to claim 15 in which R 1  and R 2  represent phenyl, 2-thienyl, 3-thienyl, 2-furyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 3-pyrrolyl or 2-pyrimidinyl, 1,3,4-thiadiazol-2-yl or 2-thiazolyl; R 3  is 4-dimethylaminophenyl, 4-dimethylamino-3-pyridyl, or 5-dimethylamino-2-thienyl; X represents oxygen or sulfur and Z represents hexafluorophosphate, fluoroborate or perchlorate. 
     
     
       17. An organic photoconductive insulating composition according to claim 15 wherein said polymeric binder has an alkylidene diarylene moiety in a recurring unit thereof. 
     
     
       18. An organic photoconductive insulating composition according to claim 15 wherein the 2,4,6-trisubstituted pyrylium dye salt is selected from the group consisting of 4-(4-dimethylaminophenyl)-2-phenyl-6-(2-thienyl)thiopyrylium fluoroborate; 4-(4-dimethylaminophenyl)-2-phenyl-6-(2-thienyl)thiopyrylium perchlorate; 2-(2-thienyl)-4-(4-dimethylaminophenyl)-6-(3-thienyl)thiopyrylium fluoroborate; 4-(4-dimethylaminophenyl)-2-(2-furyl)-6-phenylthiopyrylium perchlorate; 4-(4-dimethylamino-3-pyridyl)-2,6-diphenylthiopyrylium perchlorate; 2-(3-pyridyl)-4-(dimethylaminophenyl)-6-(2-thienyl)thiopyrylium perchlorate; 2,6-di(2-furyl)-4-(4-dimethylaminophenyl)thiopyrylium perchlorate; 4-(4-dimethylaminophenyl)-2,6-di(2-thienyl)thiopyrylium perchlorate; 2,6-di(2-thienyl)-4-(4-dimethylaminophenyl)pyrylium fluoroborate; 4-(4-dimethylaminophenyl)-2-phenyl-6-(2-pyrimidinyl)thiopyrylium perchlorate; 4-(4-dimethylaminophenyl)-2-phenyl-6-(1,3,4-thiadiazol-2-yl)thiopyrylium perchlorate; 4-(4-dimethylaminophenyl)-2-phenyl-6-(2-thiazolyl)thiopyrylium perchlorate; 4-(5-dimethylamino-2-thienyl)-2,6-diphenylthiopyrylium perchlorate or 4-(4-dimethylaminophenyl)-2-phenyl-6-(3-pyrrolyl)thiopyrylium perchlorate. 
     
     
       19. A homogeneous organic photoconductive insulating composition according to claim 15 wherein said 2,4,6 trisubstituted pyrylium dye salt and said polymeric binder form a solid solution. 
     
     
       20. An electrophotographic element comprising a conductive support and a photoconductive insulating layer coated over said support wherein said photoconductive layer comprises a 2,4,6 trisubstituted pyrylium dye salt compound having the formula: ##STR10## in which R 1  and R 2  represent a phenyl radical, thienyl, furyl, pyridyl, pyrrolyl, pyrimidinyl, thidiazolyl or thiazolyl; R 3  represent an alkylamino-substituted phenyl radical, dialkylaminopyridyl, dialkylaminofuryl, dialkylaminothienyl, dialkylaminopyrimidinyl, dialkylaminothiadiazolyl or dialkylaminothiazolyl; X represents oxygen or sulfur and Z represents an anion and wherein at least one of R 1 , R 2  and R 3  is one of the enumerated heterocyclic moieties. 
     
     
       21. An electrophotographic element comprising a conductive support and an aggregate photoconductive layer coated over said support, said aggregate photoconductive layer comprising a 2,4,6-trisubstituted pyrylium dye salt having the formula: ##STR11## in which R 1  and R 2  represent a phenyl radical, thienyl, furyl, pyridyl, pyrrolyl, pyrimidinyl, thiadiazolyl or thiazolyl; R 3  represent an alkylamino-substituted phenyl radical, dialkylaminopyridyl, dialkylaminofuryl, dialkylaminothienyl, dialkylaminopyrimidinyl, dialkylaminothidiazolyl or dialkylaminothiazolyl; X represents oxygen or sulfur and Z represents an anion and wherein at least one of R 1 , R 2  and R 3  is one of the enumerated heterocyclic moieties. 
     
     
       22. An aggregate photoconductive composition comprising a continuous electrically insulating polymer phase and at least one discontinuous phase, said discontinuous phase comprising a particulate co-crystalline complex of (i) at least one polymer having an alkylidene diarylene group in the recurring unit thereof, (ii) and a heterocyclic 2,4,6-trisubstituted pyrylium dye salt having at least one heterocyclic substituent, said heterocyclic substituent being a 5 to 6 member ring wherein said ring has at least one atom selected from the group consisting of N, O or S, provided that said heterocyclic substituent is other than pyrylium or thiopyrylium.